There is a known notification system that notifies information on wakefulness of a subject operator (see PTL 1, for example).
The notification system described in PTL 1 is formed of a control center, a plurality of terminals, and a network that connects the control center and the plurality of terminals to each other. Among them, the control center receives information on the wakefulness and associated factors acquired from the subject operator via the corresponding terminal and creates processed information based on the information on the wakefulness and associated factors. The control center then transmits the processed information to the terminal that the subject operator is using, and the terminal notifies the subject operator of the processed information. The processed information is alternatively created by the corresponding terminal in some cases.
The information on the wakefulness and associated factors described above contains physiological information, such as an electrocardiographic waveform, the heart rate, the brain wave, and the pulse, and information on whether the subject operator is present. When the information on the wakefulness and associated factors is provided in the form of an electrocardiographic waveform, peaks at 0.1 Hz and therearound provide the action levels of the sympathetic nerves and the parasympathetic nerves, and peaks at 0.3 Hz and therearound provide the action level of the parasympathetic nerves.
Examples of the processed information described above include information in the form of graphs representing the resultant action levels and information representing the distribution of the wakefulness and the position of the subject operator in the distribution. Other examples of the processed information include information representing the information on the wakefulness and associated factors and a preferable range and information representing the average of wakefulness levels in a predetermined period (one day, for example) and the current wakefulness level.